"We were disappointed the governor included such a proposal in his budget released this week. We urge you to not reauthorize this tax," Mass. Attorney General Martha Coakley and R.I. Attorney General Peter Kilmartin said in a letter to Malloy.

"Connecticut's generator tax is inappropriately raising the rates of our states' families and businesses in order to benefit Connecticut's coffers. In essence, the ratepayers of our states and others are bearing the burden of higher energy market prices," the attorneys general said.

Malloy refused to back down despite the usual communication Thursday from two neighboring states. The tax on electrical generation plants was scheduled to sunset this year but Malloy on Wednesday proposed extending it in order to retain revenue for his $44 billion, two-year spending plan.

"While we respect the opinions of our neighboring attorneys general, we have to take the appropriate action for our state," said Andrew Doba, Malloy's spokesman.

"The fact is that energy rates are down 12 percent across the board in Connecticut since the enactment of this revenue enhancement. And we look forward to further reductions in rates once the governor's comprehensive energy strategy is fully implemented," Doba said.

The energy tax is already a headache for Malloy. Lawmakers and Dominion, which owns the Millstone nuclear power plants, have accused the governor of breaking a promise to let the levy expire this year.

Malloy has also insisted that extending the tax is not a "tax increase," allowing him to say that his proposed state budget does not raise taxes. The tax was part of a deficit resolution package enacted two years ago.

The energy tax cost Millstone about $42 million this year and is expected to bring in about $76 million in each of the next two next fiscal years.

A Dominion spokesman on Wednesday vowed to pass the cost onto wholesale customers, which he said would lead to higher electric rates for business and residential users.

Coakley sand Kilmartin said they understand budget challenges and asked Malloy to let the tax sunset. They said the levy is costing New England ratepayers $58 million more for electricity and 75 percent of those costs are being borne by ratepayers outside of Connecticut.

"New England's relatively high electricity costs are an economic drag on each of our states and New England as a whole. Our offices work every day to oppose unnecessary and inappropriate electricity rate increases to protect the ratepayers of our states," the attorneys general said.